Assessment of the influence of global dimming on the photosynthetic production of rice based on three-dimensional modeling  

作　　者：ZHENG BangYou MA YunTao LI BaoGuo GUO Yan DENG QiYun 

机构地区：[1]Key Laboratory of Plant-Soil Interactions, Ministry of Education, College of Resources and Environment, China Agricultural University, Beijing 100193, China [2]China National Hybrid Rice R & D Center, Changsha 410125, China

出　　处：《Science China Earth Sciences》2011年第2期290-297,共8页中国科学（地球科学英文版）

基　　金：supported by National High Technology Research and Development Program of China (Grant No. 2006AA10Z231);National Key Technologies R & D Program (Grant No. 2007BAD87B08);Chinese Universities Scientific Fund (Grant No. 2009-3-14)

摘　　要：Observations indicate that global radiation reaching the Earth's surface has gradually decreased over the past several decades(i.e.,the "global dimming" phenomenon),while the fraction of diffuse radiation in global radiation has increased.It has been found that the increase in diffuse fraction significantly increases photosynthetic production in the canopy,but the mechanism has not been clarified.A three-dimensional light distribution model considering the geometry of incident radiation was employed in this study.This model was used to simulate the light distribution and potential photosynthetic production of rice canopy.The results indicate that the potential photosynthetic production of rice significantly increases in response to an increase in the diffuse fraction as long as global radiation does not decline greatly.The "fertilization effect" of diffuse radiation results from the reduction of leaf area with photosynthetic photon flux density(PPFD) below the light compensation point in response to an increasing diffuse fraction,and an increase in the leaf area with PPFD on the linear part of the light response curve.The increase in the diffuse fraction results in a significant increase in the photosynthetic rate of the upper canopy.High-performance computation is an easy-to-use and economic approach to overcome the computational constraints of the model.Observations indicate that global radiation reaching the Earth＇s surface has gradually decreased over the past several decades （i.e., the ＂global dimming＂ phenomenon）, while the fraction of diffuse radiation in global radiation has increased. It has been found that the increase in diffuse fraction significantly increases photosynthetic production in the canopy, but the mechanism has not been clarified. A three-dimensional light distribution model considering the geometry of incident radiation was employed in this study. This model was used to simulate the light distribution and potential photosynthetic production of rice canopy. The results indicate that the potential photosynthetic production of rice significantly increases in response to an in- crease in the diffuse fraction as long as global radiation does not decline greatly. The ＂fertilization effect＂ of diffuse radiation results from the reduction of leaf area with photosynthetic photon flux density （PPFD） below the light compensation point in response to an increasing diffuse fraction, and an increase in the leaf area with PPFD on the linear part of the light response curve. The increase in the diffuse fraction results in a significant increase in the photosynthetic rate of the upper canopy. Highperformance computation is an easy-to-use and economic approach to overcome the computational constraints of the model.

关 键 词：diffuse radiation climate change PHOTOSYNTHESIS crop simulation hlgh-performance computing functlonal-structural plant modeling 

分 类 号：S511[农业科学—作物学] TP391.41[自动化与计算机技术—计算机应用技术]